<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button>按钮1</button>
    <button>按钮2</button>
    <button>按钮3</button>
    <button>按钮4</button>
</body>
</html>
<script>
    var btn=document.querySelectorAll('button');
    for(var i=0;i<btn.length;i++){
        btn[i].onclick=changeColor;
    }
    function changeColor(){
        for(var j=0;j<btn.length;j++){
            if(btn[j] === this){
                this.style.backgroundColor='pink';
            }else{
                btn[j].style.backgroundColor=''
            }
        }
    }
</script>